Looking to open up capped chimney on 400 year old cottage

[StrumpersPlunkett]

Does anyone have any ballpark idea on cost/faff?

Bought a house based on the glorious big open fire only to find it is capped.
Any ideas help would be appreciated.
Thanks.

When you say capped do you mean blocked? I think a capped chimney just means that the end has a lid to prevent water or birds coming in. A chimney sweep can cheaply tell you whether the flue is open (smoke pellets) and whether it needs a new flue, which would usually be the biggest expense. You can get a ballpark cost of a new flue on local stove shop websites (including installation) but the cost will vary depending on the area, and then may be more if there are unusual access issues.

Thanks. We had a fire thinking it was open
Dh went outside and could see some smoke rising from the pot. But within 10 mins sittingroom was filled with smoke.

Obvs put fire out had one local handyman come round who said it was impossible that the structure of the house meant it wouldn't have a working chimney.
Didn't care that smoke was rising to start with.
We have asked previous owners who said it was their belief that it could work but had been capped.
So I guess we are hoping it won't be a very costly building job 🤞

Not stating the obvious but have you opened the little door bit above the fireplace? Should be a little handle and it opens and closes a flap. You close it I’m summer to block drafts and then open when the fire is lit

Possibly why some smoke was escaping but house filled up!

You ought always to get a chimney swept before lighting the fire for the first time, especially one that hasn't been used for years. You've no idea what might be up there. An obstruction can at the least prevent the fire drawing and make it smoke into the room, or at worst can cause the chimney itself to catch fire.

It’s probably full of birds nests or the flaps closed.

Unlikely a 400 year old cottage DS this have a working chimney!

Yikes that was really silly and dangerous to light a fire without getting a sweep in!

Woah! Def get a sweep before lighting a fire for the first time. Massive carbon monoxide risk! You need a CO2 detection meter installed for safety if you plan on using it once swept.

Is the chimney part of the old structure of the house? massive chimney stack, big fireplace (perhaps with a smaller modern one in front?
Normally "capping" means the hole at the top (which normally has a chimney pot on) is blocked up. Sometimes the flue just above the fireplace is blocked as well. Have a look with a torch.

First job, get a chimney sweep in.
Get a builder to unblock or replace the chimney pot.

Depending on the age and condition of the flue and whether or not you want a wood burner you may need the flue re-lining. This can be done by putting a flexible flue liner down and the void is then filled with vermiculite (fireproof insulation). This has to be done by a "HETAS " registered contractor and, I think, is subject to building regulations.

Of course, in the "old days" before all the safety regulations, you would have just cleared out the chimney pot, swept the flue and lit the fire....

In a house and chimney of that age you really need a full inspection including with a camera. Many (many) years ago it was permissable to use wooden beams within the construction of the chimney, but this caused so many fires it became illegal.
You will probably need a liner, as a pp had said. The stipulations in household insurance are so strict now, if you had caused a fire you probably would not have been covered. I was amazed when we had a woodburner fitted (it had been 15 years since I had had a real fire in a house), that you now have to have an annual certificate from your sweep saying that your chimney is fine and in good working condition, and insurance companies ask whether you have a real fire. Such a change from how it used to be.
Anyway, start with a sweep, they are usually very knowledgeable.

Chimneys are capped because they are unused. They remain a very useful way to ventilate and therefore de-moisturise the room they serve.
You will need a builder/oddjob man to remove the capping first. This is usually just a flagstone/slab mortared into position, as mentioned to keep chimney dry and bird free. Tell the guy who opens it that you want to use it and would like him to test the draught and install a chimney pot/stone equivalent to suit the cottage. If the 1st test is good, plenty of draw, check again when the pot is installed and then decide if you want an open fire or a log burner.
Cost for uncapping and fitting proper chimney could be between £50 and £300, depends on your type of chap who does it. I had a log burner flue and pot installed recently for £350 - it took 4/5 hours.
Negotiate the price first ! It may need scaffolding and that would be expensive but it could be done by the right man with a ladder and someone to hold it. The little door is a flue cleaner and wont help unless you have loads of soot. a simple check for soot is to get a torch and shine it up the chimney. 400 years old and the chimney should be massive with a huge void you could almost climb up.
Our house is 1620 in part and we have done almost exactly what you are planning.
Good Luck !

Gosh as others have said, you must get a sweep at the very least!

My neighbour’s house actually burnt down last year because they didn’t follow proper instructions with a wood burner.

The house is 400 years old - its had a fire in it for generations - it will have been built correctly for an open fire, Log burner will need a flue so check if you want a log burner that the flue /fire installer is HETAS registered and will supply a certificate of conformity - essential if you sell. Log burners also require carbon dioxide alarms to be fitted to comply.
When you unblock, it will be obvious if it needs a sweep but only if you want an open fire. The flue liner will keep all the major heat in the flue and will therfore not need cleaning for some time. Dont be panicked into agreeing - think logically and you will be ok !

Thank you so much this is fabulous.

The chimney is a major central structure of the cottage with fireplaces above in the bedrooms.

We had been lead to believe by the sellers that it was a well used (recently) open fire which it why it was a huge shock when the room filled with smoke. 🙃

Our open fire billowed smoke back into the room the first time we used it after it not being used for a long time. It soon stopped doing it. We had it swept before we used it and the sweep said it was fine to use and would be a case of try it and see on whether the smoke would draw up or into room!